1. Field of the Invention
This invention relates generally to formation of coatings, films and laminates. More specifically the invention relates to formation of layers of materials using controlled droplet formation and deposition techniques.
2. Description of Related Art
In the manufacture of coatings, films, and laminates it is often desirable to precisely control the physical characteristics and properties of individual layers of material laid down on a substrate. For example in the manufacture of pressure-sensitive adhesive (PSA) laminate constructions such as labels and tapes, control of physical characteristics such as the thickness, surface morphology and deformation with application of stresses, as well as material characteristics such as chemical composition, crosslinking of polymeric chains, the percent of solids in emulsions and solvents in solution, for example is desirable. This is true for an adhesive layer of such a construction, wherein properties such as tack, peel, stability, and resistance to solvents, for example, are desired to be controlled. It is also true for a release layer in such a construction, wherein properties such as release of the adhesive when used with a given PSA and underlying carrier, chemical and physical interaction with adjacent carrier and PSA layers, for example, are desired to be controlled. Also other layers of the laminate construction such as a facestock which influence overall laminate properties such its stiffness and whether the construction is self-supporting, whether the facestock can be printed, for example, are carefully designed and controlled in a PSA laminate construction product, and greater control over their properties is desirable.
In tape products and adhesive coated films dispensed from rolls, control of the properties of individual component layers is also highly desirable. Particularly since the final PSA product must be designed so as to incorporate an adhesive layer on one side that may be very aggressive, and on the opposite face incorporate a release surface, and the functionality of the two must be carefully balanced so that a desired peel force is achieved, control of the properties of these layers is critical to the functionality of the construction.
However, the need for precise control of the properties of constituent materials, individual layers, and overall performance is not limited to the forgoing examples involving PSA laminates. Many other applications, for example fabrication of electrical components having a layered construction, self-supporting polymeric resin films which can be built up in layers, layered coatings applied directly to products for protective purposes are some of many examples that can be cited.
Furthermore, many properties of layered constructions bear directly on the cost of the product including the layered construction. This is particularly true in labels and tapes and films where volume is high, for example. It would be very desirable to optimize one or more layers of a laminate so as to achieve the desired result with a minimum material requirement.